14-3-3 Sigma positively regulates p53 and suppresses tumor growth.

2003 DEC 4 - (NewsRx.com & NewsRx.net) -- 14-3-3 sigma positively regulates p53 and suppresses tumor growth. According to published research from the United States, "The 14-3-3 sigma (sigma) protein, a negative regulator of the cell cycle, is a human mammary epithelium-specific marker that is downregulated in transformed mammary carcinoma cells.

"It has also been identified as a p53-inducible gene product involved in cell cycle checkpoint control after DNA damage. Although 14-3-3 sigma is linked to p53-regulated cell cycle checkpoint control, detailed mechanisms of how cell cycle regulation occurs remain unclear," wrote H.Y. Yang and colleagues, University of Texas, M.D. Anderson Cancer Center.

"Decreased expression of 14-3-3 sigma was recently reported in several types of carcinomas, further suggesting that the negative regulatory role of 14-3-3 sigma in the cell cycle is compromised during tumorigenesis. However, this possible tumor-suppressive role of 14-3-3 sigma has not yet been characterized," the researchers wrote.

"Here, we studied the link between 14-3-3 sigma activities and p53 regulation. We found that 14-3-3 sigma interacted with p53 in response to the DNA-damaging agent adriamycin. Importantly, 14-3-3 sigma expression led to stabilized expression of p53. In studying the molecular mechanism of this increased stabilization of p53, we found that 14-3-3 sigma antagonized the biological functions of Mdm2 by blocking ...